(1) Field of the Invention
The present invention is directed to a linear buoyant antenna and a method for designing such an antenna to provide two different band capabilities in a single element.
(2) Description of the Prior Art
Buoyant Cable Antennas (BCAs) are a class of antennas unique to maritime applications. They consist of a straight insulated wire surrounded by a positively buoyant jacket material. The electrical performance of these antennas is somewhat limited owing to the underlying physics involved, and several antennas are often needed to obtain broadband frequency coverage. The present invention seeks to overcome this limitation by providing optimal multi-band performance in one single conductor antenna element.
Previous work on BCA improvements has led to antennas that have improved performance in the HF band (e.g. U.S. Pat. No. 7,868,833, entitled “Ultra wideband buoyant cable antenna element.” This improvement was only possible in a single portion of the radio spectrum and does not allow for improved performance in both the High Frequency (HF) and Very High Frequency (VHF) bands.
The use of a modular approach is disclosed in U.S. Pat. No. 8,203,495, entitled “Modular VLF/LF and HF buoyant cable antenna and method.” This teaches that low frequency signals can be received on the braid of a piece of coaxial cable that is connected in series with the HF antenna. The method taught only allows for improvements the performance of the HF antenna.